<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>宽度适配方案</title>
  <style>
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    li {
      list-style: none;
    }
    .toolbar {
      position: fixed;
      left: 0;
      bottom: 0;
      width: 100%;
      height: 50px;
      background-color: pink;
    }
    .toolbar ul {
      display: flex;
    }
    .toolbar li {
      width: 25%;
      height: 50px;
      text-align: center;
    }
    .toolbar img {
      height: 50px;
    }
  </style>
</head>
<body>
  <div class="toolbar">
    <ul>
      <li>
        <a href="#"><img src="./images/index.png" alt="" /></a>
      </li>
      <li>
        <a href="#"><img src="./images/classify.png" alt="" /></a>
      </li>
      <li>
        <a href="#"><img src="./images/car.png" alt="" /></a>
      </li>
      <li>
        <a href="#"><img src="./images/login.png" alt="" /></a>
      </li>
    </ul>
  </div>
</body>
</html>